1. Field of the Invention
The present invention relates to fuel supply devices for internal combustion engines, having a constant level chamber fed from a reservoir by a pump driven mechanically by the engine.
2. Prior Art
Mechanically driven pumps are generally directly carried by the casing of the engine so as to facilitate transmission of movement. When the engine is stopped while hot, the pump, which is no longer cooled by the fuel which flows therethrough when it is operating, heats up. If the temperature under the bonnet is very high, the fuel contained in the pump vaporizes. If attempts are made to start up the engine again before cooling, the vapor or air which occupies the pump delays suction of fuel: that results particularly in an operating jerk of the engine as soon as the float chamber has become empty, since it is not yet supplied by the pump.
A supply device has already been proposed of the type in which a capacity or chamber is interposed between the reservoir and the pump and is separated from the reservoir by a non-return valve. The upper part of the capacity is connected to a pressurized air source during starting of the engine. Air drives the fuel contained in the capacity towards the pump.
This solution requires the introduction of air into the capacity, which is unfavorable; it requires a pressurized air source; it lacks progressivity.